The invention relates, in accordance with a first aspect and the preamble of Claim 1, to a protective element having a plate which has a first longitudinal edge and a second longitudinal edge, the edges being spaced apart from each other by a distance (D), and the protective element including a pivot bearing which is arranged essentially parallel to the first longitudinal edge and/or to the second longitudinal edge, is designed for transmitting forces and by means of which, in order to absorb forces acting on the protective element, the plate can be arranged on a substructure, in particular on a device for protecting against floods or avalanches, and such that it can move with respect to this substructure in a swivelling range (S). The invention furthermore relates, in accordance with further aspects, to devices for protecting against floods or avalanches, and to a method for protecting an area against floods or avalanches.
Unfavourable climatic circumstances repeatedly and all too frequently cause enormous amounts of precipitation to turn whole areas and large parts of individual provinces into inundated areas within a very short period. It is obvious in this case that existing protective measures, such as dyke systems, barrier measures, drainage and property protection systems are often of insufficient size to withstand the excessive water levels and to contain the respective volumes of water.
Devastating inundations, for example the inundations in the Oder-Neisse area in 1997, China 1998, or else annually recurring floods (for example, in the, Rhine plain in Cologne), which have considerable economic decisively improve and supplement existing flood protection systems or to redesign them. As far as is known, measures for redesigning and renewing dyke systems concentrate essentially on the following:
The consequent expansion in capacity of retaining spaces
Stabilizing earth-filled dams using a very wide variety of measures
Eliminating the risk of earth-filled dams becoming sodden in the event of floods and heavy rainfall
Enlarging the holding capacity by raising the dyke summit and enlarging the base of dyke systems
Protection of existing buildings by means of temporarily erected stop-gaps or permanent new protection systems.
In the realization of projects of this type, ecology, dyke protection and also economic demands frequently contradict one another: popular solutions include configuring and dimensioning the capacity and design of dyke systems and retaining spaces to cope with extreme precipitation and flood conditions and also with extremely high water levels. Reinforcing and raising the dam profiles (if this is indeed possible) require huge movements of earth and the sacrificing of large areas of land. Some of the investments undertaken for large-scale retaining spaces and dykes therefore remain virtually unused for years, perhaps for decades, while considerable disadvantages to the landscape, for example as a result of high dyke summits and too great a requirement of land, are accepted at the same time. There is therefore a demand for movable or mobile flood protection systems which require significantly less land.
In the city centre in Cologne, mobile flood protection walls, which are known as the xe2x80x9cCologne barrierxe2x80x9d have been installed for some time. During periods of normal or low water, the elements required for this are stored in suitable places, so that the bank of the Rhine which is touristically and historically attractive and is also important in terms of town planning is not permanently disadvantageously affected in terms of town planning because of this flood protection. In the event of a flood alarm, within the period of approximately 24 to 48 hours until the flood strikes, the protective elements have to be taken out of the store, transported to the location of use and installed there by professionals. This requires a permanent, specially trained task force. This task force and also the storage, transportation and installation means considerably increase the costs of the protection walls; a fairly long reaction time to an acute, short-term risk of flooding may be regarded as a further disadvantage of this system.
EP 0 741 205 A1 disclosed a movable or mobile flood protection system, in which protective elements can simply be swivelled from a horizontal position into a vertical position, or can be installed upright. In a first embodiment, this system has a holding chamber which is divided into a floodable floating chamber and a swivel-in chamber, and has one or more wall elements. These wall elements themselves consist of a pontoon part, which can be swivelled into the floating chamber and is made buoyant by floods, and of a counterweight part, which can be sunk into the swivel-in chamber, and also of a supporting element which is designed, for example, as a sheet-pile wall and in whose head region the wall elements are mounted in a manner which allows them to swivel. In a second embodiment, the system has all elements which can be latched into an anchorage. In both systems proposed, it could be regarded as disadvantageous that the forces acting, because of the accumulated water, on the protection walls are distributed unfavourably since they act virtually only on the pivot point of the protection wall and on the lower seal thereof. In addition, the complete swivelling back of the wall elements according to the first embodiment can be made considerably more difficult due to dirt accumulated in the floating chamber, which faces towards the flood. Moreover, the seal-tightness of the protection wall at just a low flood level is not unconditionally ensured: thusxe2x80x94in particular in the second embodimentxe2x80x94the hydrostatic pressure can separate the seal at the lower end of the protection wall from the sheet-pile wall, if the water level is too low, so that this pressure is exceeded by means of the banking-up pressure, which acts on the protection wall above the bolt.
Avalanche barriers are known in all alpine countries in Europe and generally cause an avalanche of snow to be stopped. Disfigurement of the landscape by the often wide avalanche barriers which can largely be seen as horizontal rows is, of necessity, accepted because of the protective action of these systems which are often significant to survival.
The continuing heating up of the Earth""s surface is accompanied by the permafrost boundary being shifted to greater heights above sea level. This has, inter alia, the consequence that many mountain slopes which have been stabilized for hundreds of years by the permafrost (permanent frost all year round) can suddenly become unstable and slip; the consequence could be landslides and avalanches of scree in areas which were previously not at risk. The risk of such avalanches of scree occurring rises especially when the thaw starts (generally in early summer). Appropriate protective measures are not known to date.
The object of the invention comprises proposing a protective element and also devices and a method for protecting an area against floods or avalanches, which can be used to overcome the indicated problems from the prior art and to provide alternative solutions.
The object is achieved, in accordance with a first aspect, by the features of independent Claim 1, by the protective element mentioned at the beginning being characterized in that the pivot bearing is of sealed design andxe2x80x94in order to compensate for forces acting on the plate and on the bearingxe2x80x94is arranged spaced apart at a maximum of a quarter of the distance (D) from a geometrical axis or gravity axis of the plate, which axis runs between the first and second longitudinal edges and essentially parallel to the longitudinal edges. In accordance with further aspects, the object is achieved by a device for protecting against floods or avalanches, according to Claim 5, and also by a method for protecting an area against floods or avalanches, according to Claim 17. Preferred developments according to the invention of the protective element, of the device and of the method arise from the dependent claims.